Density Functional Theory for Matter under Extreme Conditions

This project focuses on the advancement, implementation, and use of finite-temperature density functional theory (DFT), especially in orbital-free form, to achieve simulations (ab initio molecular dynamics, path integral MD, and beyond to approximate quantum dynamics) of matter under extreme conditions. Examples include warm dense matter (WDM) and systems in ultra-high magnetic fields. Closely related research in ground-state DFT and current-density functional theory is also part of our effort.

Differing sectors of our work are supported under U.S. DOE Grant DE-SC0002139 and U.S. NSF grant DMR-1912618.

This site focuses on providing a coherent description of the problems and tools, both theoretical and technical, used throughout the disjoint community of researchers in order to promote the subject and the community.

Latest News

(All News)

July 20, 2021

Another tool for orbital-free DFT development now is available. Our OFDFT-modified version of the APE (Atomic Pseudopotential Engine) code now is downloadable from the Computation page. The modifications were done by Kai Luo (now at Nanjing University of Science and Technology) when he was here. Recently Héctor Francisco revived the code, added a kinetic energy density functional as an illustrative exercise, and revised Kai's notes.

May 2, 2021

Welcome also to Dr. Héctor Francisco Rodríguez as a post-doctoral associate on the NSF project. He completed his Doctor en Ciencias Químicas in January under the guidance of Prof. José Luis Gázquez (Univ. Autónoma Metropolitana, Mexico City). His thesis title (translated) was "Approximations for the Non-interacting Kinetic Energy in Terms of the Electron Density".

March 30, 2021

We are pleased to welcome Dr. Tun Sheng Tan as a post-doctoral associate. He completed his Ph.D. with Prof. John Rehr (Univ. of Washington) this past December. His thesis title was "Theory of Finite-Temperature and Non-equilibrium X-ray Absorption Spectra". For the moment, he is working remotely.

Jan. 25, 2021

Congratulations to Sandipan Dutta! He has accepted a new permanent position at Birla Institute of Technology in Pilani, India. He completed his Ph.D. here with Jim Dufty in 2013, including several publications on the uniform electron gas; see the Publications page. Then he had two postdocs in South Korea working on problems at the interface of charged particles and biology.

Nov. 23, 2020

We have corrected a confusing inconsistency of nomenclature regarding the Cancio and Redd kinetic energy density functionals in our Reference Data Functional Glossary of orbital-free KE density functionals. We thank Dr. Susi Lehtola for pointing out the anomaly.

Nov. 20, 2020; Oct. 21, 2020

Two Open Post-doctoral Positions

Both of these postions now are filled.

Oct. 21, 2020 - Two Open Post-doctoral Positions Unexpected disruptions have led to our having two post-doctoral positions available immediately. The Principal Investigator is Prof. Sam Trickey. Co-Principal Investigators are Profs. Jim Dufty (Florida) and Antonio Cancio (Ball State).

One position (funded by NSF) is to advance de-orbitalized and orbital-free ground-state exchange-correlation functionals. An example of recent progress is Phys. Rev. B 102, 121109(R) (2020) . Challenges include analysis of the consequences of de-orbitalization upon constraint satisfaction, numerical stability of density-Laplacian-containing functionals, and first principles construction of orbital-free meta-GGAs.

The other (funded by DOE) is more on the free-energy DFT side, including systematic free energy extension of the very new r2SCAN-L orbital-free meta-GGA exchange-correlation functional, exploration of a novel approach to atomic shell-structure in a single-point, orbital-free kinetic energy density functional, and extension of time-dependent DFT to non-zero temperature without certain restrictive assumptions in the proofs. Examples of relevant prior work include Phys. Rev. B 101, 075116 (2020) and Phys. Rev. E 98, 033203 (2018).

Both positions require a solid background in many-electron theory as well as demonstrated ability to render new schemes in major electronic structure codes. Positions are tenable for up to 3 years.

Interested candidates should send a current curriculum vitae (including publication list) and contact information (email and phone numbers) for three references to Prof. Sam Trickey, trickey at ufl.edu .

Oct. 3, 2020

Congratulations to Daniel Mejía Rodríguez who has gone to Pacific Northwest National Laboratory. He will continue as a valuable collaborator. Also welcome back Angel Martín Albavera Mata, who has just begun as a post-doc in the Center for Molecular Magnetic Quantum Materials. He was a student visitor in our group in Spring 2018.

May 13, 2020

Post-doctoral position open: The project is to develop deorbitalized and orbital-free density functional exchange-correlation approximations. It is in collaboration with Antonio Cancio of Ball State Univ. The position is funded by NSF. Initial appointment is for one year with the possibility to extend it for up to three years total. Details are in the advertisement letter.

May 11, 2020

Congratulations to Daniel Mejía Rodríguez. His work on deorbitalized exchange correlation functionals and their coding led to his inclusion as one of the co-authors of the review article about the latest version of the NWChem code suite. His name is highlighted (in Gator Orange) in the author list on the Publications page.

May 7, 2020

We have been notified that National Science Foundation has awarded a grant to Sam Trickey and co-PI Antonio Cancio (Ball State Univ.) for work on meta-GGA exchange-correlation functionals that do not depend explicitly on the Kohn-Sham kinetic energy density ("deorbitalized" functionals).

April 13, 2020

Generalized hydrodynamics revisited, by Jim Dufty, Kai Luo (alumnus of our group), and Jeff Wrighton has appeared as an Editors Suggestion in Phys. Rev. Research. Congratulations gentelemen! The pdf is accessible from the Publications page.

March 9, 2020

Slides from the three presentations from our group that were supposed to have been given last week at the cancelled Amer. Phys. Soc. March meeting have been posted at Presentations.

Feb. 10, 2020

In what has become a valuable annual visit, Profs. José Luis Gázquez (Universidad Autónoma Metropolitana, Cd. de México) and Alberto Vela (CINVESTAV, Cd. de México) are here this week. Discussions include work under way on derivative-discontinuity shifted density functional approximations (see very recent J. Phys. Chem. A article under Publications), locally parametrized non-separable generalized gradient approximations (also on the Publications page), and a systematic strategy for moving beyond generalized gradient approximations without invoking orbital dependence.

Feb. 03, 2020

We are pleased to welcome Prof. Dr. Notker Rösch (Technische Universität München) for a few days to discuss, inter alia, the challenge of accurate spin-manifold calculations with orbital-independent density functional approximations.

Dec. 23, 2019

Several recently submitted papers have been posted at Publications.

Sept. 5, 2019

Congratulations to Kai Luo, who has taken up a new position at the Carnegie Institution for Science in Ron Cohen's group. Kai joined our group in Jan. 2017 and, among other achievements, led the work on the LKT kinetic energy density functional as well as working on the relationship of the Kubo-Greenwood scheme to time-dependent DFT. His new web page is at the Carnegie Science Earth and Planets Laboratory site.

July 9, 2019

A presentation from last week, about our de-orbitalized metaGGA functionals (especially SCAN-L, the deorbitalized SCAN), has been posted at Presentations.

May 30, 2019

PDFs of four recent presentations (two each from this year and 2018) from group members have been added to the Presentations.

Jan, 22, 2019

Our LKT orbital-free kinetic energy density functional [Phys. Rev. B 98, 041111(R) (2018)] has been added to the main branch of the public PROFESS repository. Kai Luo ("L" in "LKT") contributed the code. Thanks to the authors and maintainers of PROFESS.

Oct. 18, 2018

Alert! A bug in the pressure calculation of our PROFESS@QE package has been fixed. Please see the Computation page to download the corrected tarball.

Sept. 24, 2018

Please join us in welcoming Dr. Dongdong Kang for a one-year visit in our group. He is from the Department of Physics, National University of Defense Technology, Changsha China.

April 25, 2018

We've initiated a new resource. Under Reference Data, we've put up a first implementation of a pop-up periodic table that enables the user to get atomic kinetic energies for many different orbital-free KE functionals. We will be improving and extending this and other technical data resources. Suggestions are welcome. Thanks to Kai Luo and Daniel Mejia-Rodiguez for doing the calculations and preparing the presentation.

April 16, 2018; update May 23

For those who read Spanish, the article about the ceremony for Sam Trickey's admission as a Corresponding Member of the Academia Mexicana de Ciencias in the "Boletin Informativo" is here. A related article is at the Academy's news site. And an interview is here .

March 12, 2018

It is a pleasure to welcome Angel Martín Albavera Mata for a three-month visit. Angel is a Ph.D. student with Prof. Alberto Vela at CINVESTAV-Zacatenco in Mexico City. His work here will be on testing and validation of the performance on solids of the various Mexican collaboration exchange-correlation functionals. This is an important topic for the progress of orbital-free DFT, as those functionals are all generalized-gradient approximations.

Feb. 14, 2018

After repeated, almost inexplicable delays, our Valentine's present is the appearance (at last!) of our generalized gradient approximation for the exchange-correlation free energy, KDT16. See Phys. Rev. Lett. 120, 076401 (2018) on Publications.

August 15, 2017

Jeff Wrighton has been a collaborator with Jim Dufty for several years. It is a pleasure to announce that Jeff has formally joined the group.

July 24, 2017

With appreciation for his many contributions, mixed with understandable (we trust) regret at his departure, we are proud to report that Valentin Karasiev has taken a Staff Scientist position in the High-energy Density Physics Group of the Laboratory for Laser Energetics, University of Rochester.

June 23, 2017

Today we are happy to announce the first public release of our Kubo-Greenwood electrical conductivity post-processor package for use with QuantumEspresso. The KGEC code and Guide are available from our Computation page and the paper that describes both the underlying analysis and the implementation is downloadable from Publications.

June 11, 2017

It is gratifying to report that the book Frontiers and Challenges in Warm Dense Matter [Springer] continues to draw interest as measured by eBook chapter downloads. The numbers are 1,572 [2016], 1,597 [2015], and 1,822 [2014]. The book grew out of the 2012 IPAM long program on high energy density physics in which several members of our group participated. The book editors are Frank Graziani, Michael Desjarlais, Ronald Redmer, and Sam Trickey.

April 3, 2017

Congratulations to Lázaro Calderín, who has gone to the College of Engineering, Univ. of Arizona, as Assistant Research Professor. Among other contributions, Lázaro led the Kubo-Greenwood code development project.

March 23, 2017

The LibXC initialization test for our KSDT functional has been updated to include C code as well as the previous Fortran code. See the "LSDA Exchange-Correlation Free Energy Subroutines" item on the Computation page and the paper on the underlying, the algorithms, and implementation is on our

March 19, 2017

Newly posted on the Presentations page are the PDFs for our four presentations at the APS March meeting last week.

Dec. 19, 2016

On the Publications page, take a look at the manuscript announcing our new finite-T Generalized Gradient Approximation exchange-correlation functional, KDT16. It reduces to PBE at T=0 K but gives noticeably different pressures in, for example, Al and deuterium at temperatures into the WDM regime.

Dec. 12, 2016

We are happy to announce that Sam Trickey has been named a Corresponding Member of the Academia Mexicana de Ciencias in recognition of his long, extensive involvement in materials physics and chemical physics research in México.

July 1, 2016, Update Oct. 31, 2016

TWO POSTDOC POSTS

Both positions now have been filled. For context, the advertisement letter still is posted.

June 15, 2016

The LibXC implementation of our KSDT local spin density approximation exchange-correlation free energy functional will not initialize properly if called in the standard way. A HOWTO file which explains the extra initialization and a set of simple test routines now is available from Computation.

May 10, 2016; Update June 13

Deb got married! Congratulations to him and Aindrila. And he is leaving. We wish him well. The wedding celebration reception here in Gainesville was May 1st. A photo from that event is on the People page.

March 2, 2016

Version 2 of PROFESS@QuantumEspresso is released! The main change is utilization of PROFESS version 3.0 and QuantumEspresso version 5.2.1. The README and new tarball are downloadable from Computation. Licensure continues to be GNU GPL. Give the package a try. Let us know what you think.

Dec. 18 and 23, 2015

Our KSDT LSDA exchange-correlation free energy functional is in LibXC v3.0.0, which is to be released. (Presently it is listed as KSDT2; we have asked that this be corrected.) We will provide a test code and data downloadable from here when the LibXC version is released. Meanwhile, the LibXC development version that includes KSDT is downloadable from the LibXC svn repository. Go to the LibXC download page and scroll down for the instructions.

June 17, 2015

Subroutines to evaluate the LSDA exchange-correlation free energy functional now are downloadable from the Computation page. Details of this KSDT functional, which was obtained by fitting to high-precision path-integral Monte Carlo data, are in Phys. Rev. Lett. 112, 076403 (2014); see Publications The subroutines are substantially the same as those in our PROFESS@Quantum-Espresso (version 1) package. As customary, licensure is GNU GPL.

June 10, 2015

Travis Sjostrom of Los Alamos National Lab (and an alumnus of our group) is visiting. He will present a talk on his recent work on Friday, 12 June, 2:00 pm.

Jan. 22, 2015

We are pleased to welcome Dr. Lázaro Calderín to the group. He began last week. Until logistics of his move from Penn State to Gainesville are completed, he will be working remotely. Initially he will be working on temperature effects in calculated spectra.

Nov. 7 and 19, 2014

High-precision, smooth fits to various commonly encountered combinations Fermi-Dirac integrals are treated in our new paper. The fits have smooth derivatives, an important property lacking in several of their predecessors. The reprint is available on the publications page. Nov. 19 update: GPL-licensed software for these fits now is available for download from the Computation page.


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